In a mobile communications network, a User Equipment (UE) connects to the network via the radio access network, and more specifically through a radio access link to a Radio Access Node, such as a NodeB, an evolved Node B (eNodeB) or other equivalent node including a gNodeB. Transmissions between the UE and a node in the network typically involve at least a wireless channel between a radio access node and the UE. Typically there are further wired connections between the radio access node and other nodes in the radio access network or a core network. Mobile networks have historically been designed to support the mobility of a UE (although mobility is not required in a UE). To maintain the connection between the UE and the network as the UE moves, handover procedures have been developed to allow a UE's session to be preserved as the radio access link moves between one access node and another. This process is known as a handover.
In developing handover procedures, the disruption of a connection with a UE as the UE is handed over from one eNodeB to another is expected. This has an impact on the reliability of a connection. A human operator using the mobile network for a voice call may not notice the disruption, but a data session for critical tasks may not be as forgiving.
The reliability of a connection is defined as a specified probability of successful transmission in a given time frame. For Ultra-Reliable Low Latency Connections (URLLC), a common reliability requirement is 1×10−5. This means that 99.999% of packets transmitted must be correctly received within the latency requirement. The latency requirement can vary based on the needs of the service. It has been noted that there are now use cases in which LTE based networks cannot provide connections that guarantee the latency required by real-time applications. In order to ensure reliability of the radio access channel, existing network designs, including the Long Term Evolution (LTE) standards promulgated by the Third Generation Partnership Project (3GPP), make use of error correcting mechanisms such as a Hybrid Automatic Repeat reQuest (HARQ). While HARQ and other similar mechanisms can provide a certain degree of reliability, the reliability may come at the cost of an increased latency. If the latency requirement is 1 ms or less, then HARQ and Automatic Repeat reQuest (ARQ) may not be suitable, as they can increase the latency of the transmission.
In order to provide both reliable and low latency connectivity, other techniques are required especially in mobility scenarios. In scenarios of high mobility or in ultradense deployments, the number of handovers that a UE may be subject to may further adversely impact the ability to meet the reliability and latency requirements.
Accordingly, there is a need for a system and method that at least partially addresses one or more limitations of the prior art.
This background information is provided to reveal information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.